A reliable technique to identify superior quality clones from tea germplasm

Lopez, S. Joseph; Thomas, Jibu; Pius, P.K.; Kumar, R. Raj; Muraleedharan, N.

doi:10.1016/j.foodchem.2004.10.005

Cited by 13 publications

(3 citation statements)

References 10 publications

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“…(−)-Epicatechin, as the endogenous substrate of PPO, was also found in other plant tissues, e.g. litchi pericarp , apple , and tea germplasm . In the following experiments, longan PPO activity was detected at 440 nm to endogenous substrate−enzyme system and at 400 nm to exogenous substrate−enzyme system.…”

Section: Resultsmentioning

confidence: 74%

Comparison on Characterization of Longan (Dimocarpus longan Lour.) Polyphenoloxidase Using Endogenous and Exogenous Substrates

Jian

Zhang

et al. 2010

J. Agric. Food Chem.

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Longan polyphenoloxidase (PPO) was extracted and partially purified using ammonium sulfate precipitation and dialysis. The PPO characterizations were compared using endogenous substrate (-)-epicatechin and exogenous substrate catechol. The optimal pH and optimal temperature for the PPO activity were different when reacting with both substrates. The addition of ethylenediaminetetraacetic acid disodium salt into both substrate-enzyme systems exhibited the same lowest inhibition of the PPO activity. L-ascorbic acid and L-cysteine were the best inhibitors to endogenous substrate-enzyme system, while L-ascorbic acid and glutathione were most effective inhibitors to exogenous substrate-enzyme system. Cupric (Cu2+), ferric (Fe3+), and ferrous (Fe2+) ions accelerated the enzymatic-catalyzed reactions of both substrates. Kinetic analysis indicated that longan PPO strongly bound endogenous substrate but possessed a higher catalytic efficiency to exogenous substrate, and moreover, (-)-epicatechin was determined as the optimal substrate for longan PPO. This study is useful to exactly illuminate the enzymatic-catalyzed browning mechanism of postharvest longan fruit.

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Section: Resultsmentioning

confidence: 74%

Comparison on Characterization of Longan (Dimocarpus longan Lour.) Polyphenoloxidase Using Endogenous and Exogenous Substrates

Jian

Zhang

et al. 2010

J. Agric. Food Chem.

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“…However, no attempts have been made in systematic characterization of tea germplasm using biochemical parameters of Sri Lankan tea genetic resources. On the contrary, some other tea producing countries such as China, Japan, India and Kenya have used biochemical constituents like total catechins and their fractions, total polyphenols, chlorophylls, carotenoids and caffeine in the fresh leaf as discriminative markers for characterizing their tea germplasms to evaluate diversity and genetic potential warehoused in the germplasm (Magoma et al, 2003;Chen & Zhou, 2005;Lopez et al, 2005;Saravanan et al, 2005;Gulati et al, 2009;Sabhapondit et al, 2012).…”

Section: December 2013mentioning

confidence: 99%

“…Fermentation is normally done for a shorter period to maximize the amount of TF. Prolonged oxidation results in deterioration of black tea quality, and it was observed that TF reached a maximum at the optimum oxidation time and showed a decline in quality if the processed dhool was over-oxidized during a longer period of fermentation (Cloughley, 1980;Lopez et al, 2005). Therefore, the optimum time of fermentation is a critical determinant of the quality of black tea.…”

Section: Cultivar Variations On Biochemical Constituentsmentioning

confidence: 99%

Use of biochemical compounds in tea germplasm characterization and its implications in tea breeding in Sri Lanka

Kottawa-Arachchi¹,

Gunasekare²,

Ranatunga³

et al. 2013

J. Natn. Sci. Foundation Sri Lanka

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Thirty five tea germplasm accessions selected to represent the germpalsm collection of Sri Lanka was used for biochemical characterization based on the biochemical compounds present in the fresh tea leaf. Rate of fermentation, crude fibre content, total polyphenols, total catechins, chlorophyll-a, chlorophyll-b and total carotenoids were analysed. Principal component analysis (PCA) using 7 biochemical parameters and clustering on first three principal components accounted for 87 % of the total variation and delineated the 35 accessions into 4 clusters. Biochemical parameters such as fermentation rate, total polyphenols, total catechins and plant pigments in green leaf were important in explaining the biochemical variation. The selected 35 accessions could also be categorized into 4 groups based on the fermentation rate. Estate selections (PK2, N2, DUN7, S106, DT1, TC9, WT26 and NAY3) and some introductions (TRI777, INTRI6 and VHMOR) recorded the highest total polyphenols and catechin content. Besides, ASM4/10, TRI2016, TRI2025 and TRI2043 showed the highest content of chlorophylls and total carotenoids. The significant variation of the selected biochemical compounds detected in the present study indicated the high genetic diversity of tea germplasm in Sri Lanka. Results suggests that accessions PLLG2, VHMOR, DUN7 and WT26 possess unique characteristics such as rapid fermentation, high amount of polyphenols and catechins, and these could be used as potential parents for future tea breeding programmes after analyzing other complementary traits. The present study provides useful guidelines on the use of fresh leaf biochemical parameters such as the rate of fermentation, total polyphenols, total catechins, chlorophylls and carotenoid content in characterizing the Sri Lankan tea germplasm.

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Determination of alkaloids and phenolic compounds in black tea processed by two different methods in different plucking seasons

Türkmen¹,

Velioğlu²

2007

J Sci Food Agric

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The effects of two different rolling methods and three tea plucking seasons on alkaloids and phenolics, mainly flavan-3-ols and theaflavins, in black tea were studied using an improved high-performance liquid chromatographic method. Better separation of all tea compounds analyzed -the most important factor for their identification and quantitation -was achieved only with long elution gradients, which overcame the limitations of previously reported methods. Precision of the assay method was very high since intra-day and inter-day variations were within 0.76% and 1.66%, respectively. All analytes exhibited good linearity over the range evaluated with a correlation coefficient of 0.9987-1.000. Among the four solvents evaluated, 80% methanol was the most solvent for extracting individual tea compounds. The extraction method applied exhibited good repeatability (CV: 0.39-3.29%). The content of tea compounds analyzed varied with processing method and plucking season. Teas processed using the Cay-Kur method contained higher levels of identified phenolic compounds than orthodox teas, but their alkaloid content was similar to each other. The most abundant alkaloid in teas was caffeine, ranging from 17.84 mg g −1 dry weight in September plucking to 23.79 mg g −1 dry weight in May plucking. With respect to phenolic compounds, theaflavins were at the highest level, 14.27 mg g −1 dry weight, in Cay-Kur tea processed in May.

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A reliable technique to identify superior quality clones from tea germplasm

Cited by 13 publications

References 10 publications

Comparison on Characterization of Longan (Dimocarpus longan Lour.) Polyphenoloxidase Using Endogenous and Exogenous Substrates

Comparison on Characterization of Longan (Dimocarpus longan Lour.) Polyphenoloxidase Using Endogenous and Exogenous Substrates

Use of biochemical compounds in tea germplasm characterization and its implications in tea breeding in Sri Lanka

Determination of alkaloids and phenolic compounds in black tea processed by two different methods in different plucking seasons

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